Graphene is a one-atom thick layer of carbon atoms forming six-membered rings. Graphene and graphene-like substances may be referred to collectively as polygonal carbons. Graphene has many potential uses. It has excellent electromechanical properties and can be used as a supercapacitor. Measurements have shown that graphene has a breaking strength many times greater than steel. In addition to having high mechanical strength by itself, graphene can be used to make mechanically strong graphene-polymer composites. Graphene can also be used as a magnetic material, because the edges of graphene sheets have non-binding pi-electrons giving rise to edge states.
Polygonal carbons like graphene can also be used as building blocks of semiconductor devices. The pi-electrons discussed above can give such material electronic transport properties. Graphene has, for example, been found to be a one-dimensional ballistic conductor over micron-scale distances at room temperature. The advantages of graphene include very high current carrying ability, ballistic and coherent transport, and the fact that graphene structures can be either metallic or semiconducting. Properly nano-patterned graphene ribbons can serve as transparent wires to conduct electrical currents.